Wu Lanlan, Wu Jun, Liu Yanxia, Gong Xiaodi, Xu Jianlong, Lin Dongzhi, Dong Yanjun
Development Center of Plant Germplasm Resources, College of Life and Environment Sciences, Shanghai Normal University, Shanghai, 200234, China.
Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, No.1 West Beichen Road, Chaoyang District, Beijing, 100101, China.
Rice (N Y). 2016 Dec;9(1):67. doi: 10.1186/s12284-016-0134-1. Epub 2016 Dec 1.
Chloroplast plays a vital role in plant development and growth. The pentatricopeptide repeat (PPR) gene family is one of the largest gene families in plants. In addition, cold stress affects a broad spectrum of cellular components, e.g. chloroplast, and metabolism in plants. However, the regulatory mechanism for rice PPR genes on chloroplast development still remains elusive under cold stress.
In this paper, we characterized a new rice PPR gene mutant tcd10 (thermo-sensitive chlorophyll-deficient mutant 10) that exhibits the albino phenotype, malformed chloroplast and could not survive after the 5-leaf stage when grown at 20 °C, but does the normal phenotype at 32 °C. Map-based cloning, followed by RNA interference and CRISPR/Cas9 genome editing techniques, revealed that TCD10 encoding a novel PPR protein, mainly localized to the chloroplasts, with 27 PPR motifs, is responsible for the mutant phenotype. In addition, TCD10 is specific expression in tissues. The disruption of TCD10 resulted in an evidently reduced expression of chloroplast-associated genes under cold stress (20 °C), whereas they did recovered to normal levels at high temperature (32 °C). These results showed an important role of TCD10 for chloroplast development under cold stress.
The TCD10 encodes a novel rice PPR protein, mainly located in chloroplasts, which is important for chloroplast development, growth and the maintenance of photosynthetic electron transport and its disorder would lead to an aberrant chloroplast and abnormal expressions in these genes for chloroplast development and photosynthesis in rice under cold stress.
叶绿体在植物的发育和生长中起着至关重要的作用。五肽重复序列（PPR）基因家族是植物中最大的基因家族之一。此外，冷胁迫会影响植物细胞的多种组分，如叶绿体，以及植物的新陈代谢。然而，在冷胁迫下，水稻PPR基因对叶绿体发育的调控机制仍不清楚。
本文鉴定了一个新的水稻PPR基因突变体tcd10（热敏叶绿素缺乏突变体10），该突变体表现出白化表型、叶绿体畸形，在20℃下生长至5叶期后无法存活，但在32℃时表现出正常表型。通过图位克隆，随后采用RNA干扰和CRISPR/Cas9基因组编辑技术，揭示了编码一种新型PPR蛋白、主要定位于叶绿体且含有27个PPR基序的TCD10导致了突变体表型。此外，TCD10在组织中特异性表达。TCD10的缺失导致冷胁迫（20℃）下叶绿体相关基因的表达明显降低，而在高温（32℃）下它们恢复到正常水平。这些结果表明TCD10在冷胁迫下对叶绿体发育具有重要作用。
TCD10编码一种新型水稻PPR蛋白，主要位于叶绿体中，对叶绿体发育、生长以及光合电子传递的维持具有重要作用，其功能紊乱会导致冷胁迫下水稻叶绿体异常以及叶绿体发育和光合作用相关基因的异常表达。
